JP3953665B2 - Valve timing change device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus that is provided in an internal combustion engine and that varies the valve timing of at least one of an intake valve and an exhaust valve, and more particularly to a valve timing changing apparatus that is driven by fluid pressure.
[0002]
[Prior art]
This type of valve timing changing device is a device that varies the opening / closing timing of an intake valve, an exhaust valve, or both valves of an internal combustion engine. The aim of having this device is to improve intake efficiency, improve fuel efficiency, clean exhaust gas, etc. by taking in and exhausting air at the optimal timing according to the rotational speed, load, and other conditions of the internal combustion engine. is there.
[0003]
An example of a conventional valve timing changing device is disclosed in Japanese Patent Laid-Open No. 10-89020. In the device disclosed in Japanese Patent Laid-Open No. 10-89020, a vane rotor (impeller) having four vanes (blades) is provided on a camshaft, and a housing having four protrusions is provided so as to cover the vane rotor and the vane rotor. Is provided so as to be relatively rotatable. The housing is fixed to a driven gear, and the driven gear is connected to the crankshaft and receives rotational power from the crankshaft.
[0004]
There are valleys between the four vanes in the vane rotor, and the vane rotor has four valleys. In addition, a recess is formed between each of the four protrusions in the housing, and the housing has four recesses. The four vanes of the vane rotor are respectively accommodated in four recesses in the housing. Further, the four protrusions of the housing are accommodated in four valleys of the vane rotor, respectively. In this way, the vanes and the ridges are alternately positioned in the circumferential direction, and each recess in the housing is partitioned by the vanes. Due to the combined structure of the vane rotor and the housing, an advance pressure chamber and a retard pressure chamber are formed on both sides of the vane in the circumferential direction. There are four advance pressure chambers and four retard pressure chambers in the entire device. Hydraulic pressure is selectively supplied from an oil control valve (OCV) to the advance pressure chamber and the retard pressure chamber. Oil passages from the oil control valve to the advance pressure chamber and the retard pressure chamber are provided independently for advance and retard.
[0005]
By applying hydraulic pressure to the advance pressure chamber, the rotational phase of the vane rotor advances relative to the housing. Conversely, by applying hydraulic pressure to the retard pressure chamber, the rotational phase of the vane rotor is delayed relative to the housing. The rotation angle range in which the vane and the protrusion of the vane rotor are not in contact with each other is the range of the angle at which the vane rotor can rotate relative to the housing, and the range of the rotation phase difference that can be taken between the vane rotor and the housing. It is. The housing is fixed to a driven gear, which is connected to the crankshaft and receives rotational power from the crankshaft, while the vane rotor is fixed to the camshaft. Therefore, by adjusting the rotational phase between the vane rotor and the housing, the rotational phase between the crankshaft and the camshaft is adjusted, and consequently the valve timing of the internal combustion engine is changed.
[0006]
The amount of oil that transmits hydraulic pressure to the advance pressure chamber and the retard pressure chamber leaks through the gap between the vane rotor and the housing, that is, if the oil pressure of the pressure chamber is low, the oil control valve leads to the advance pressure chamber or the retard pressure chamber. The time from the supply of hydraulic pressure to the rotation of the vane rotor becomes longer, and the operation responsiveness of the valve timing changing device is lowered.
[0007]
When the crankshaft rotation speed is low, the oil pump rotation speed is also low, so the pressure of oil supplied from the oil control valve is low. Thus, when the oil pressure is low, if the oil tightness of the pressure chamber is low, the phase of the vane rotor with respect to the housing is not stable, and the valve timing becomes unstable.
[0008]
In the valve timing changing device disclosed in JP-A-10-89020, a seal plate is provided at the tip of the vane and the tip of the ridge, and the seal plate is urged by a leaf spring. The leaf spring at the tip of the vane urges the seal plate outward (in the radial direction and outward), and presses the seal plate against the bottom surface of the recess in the housing. The leaf spring at the tip of the ridge portion urges the seal plate inward (in the radial direction and inward), and presses the seal plate against the surface of the valley portion of the vane rotor. Thus, by providing the biased seal plate at the tip of the vane and the tip of the ridge, respectively, the sliding surface between the outer periphery of the vane rotor and the inner periphery of the housing is closed with the seal plate, and the pressure chamber Increases oil tightness.
[0009]
[Problems to be solved by the invention]
In the valve timing changing device disclosed in Japanese Patent Laid-Open No. 10-89020, as described above, the sliding surface between the outer periphery of the vane rotor and the inner periphery of the housing is closed with the seal plate biased by the leaf spring. The oil tightness of the chamber is improved. However, in the prior art structure in which the seal plate is always urged and in contact with the inner peripheral surface of the recess in the housing and the outer peripheral surface of the valley portion in the vane rotor, the entire length in the axial direction of the vane rotor (the thickness of the vane rotor) The housing and the vane rotor are in contact with each other at eight locations, and the sliding resistance between the housing and the vane rotor is considerably large.
[0010]
The large sliding resistance between the housing and the vane rotor reduces the operation responsiveness of the valve timing changing device, and also makes the operation unstable when the internal combustion engine speed is low and the hydraulic pressure supplied from the oil pump is low. To do. Moreover, in the structure in which the seal plate is always in contact, the contact surface is worn, and the seal plate needs to be replaced according to the operation time of the internal combustion engine. Furthermore, in a structure that uses a seal member such as a seal plate to maintain oil tightness, parts such as a seal member and a urging leaf spring are required, which increases the number of parts, which in turn increases manufacturing costs.
[0011]
Of course, in the above-described conventional valve timing changing device, if the seal plate is simply removed, the sliding resistance due to the contact of the seal plate at all times is eliminated, but the oil tightness is lowered. If the conventional valve timing changing device adopts a structure in which a seal member such as a seal plate is simply removed, the outer periphery of the vane rotor and the inner periphery of the housing face each other with a small gap. It is practically difficult to achieve sufficiently high axial alignment accuracy in the coupling between the vane rotor and the camshaft and in the coupling between the housing and the driven gear to the extent that the gap can be kept constant due to manufacturing cost constraints. is there. Therefore, in the structure in which the seal member such as the seal plate is simply removed from the conventional one, the axial alignment accuracy between the vane rotor and the housing becomes insufficient, and the gap is too wide on one vane side, resulting in insufficient oil tightness. On the vane side opposite to 180 degrees, there is no gap, and the vane rotor and housing are in direct and strong contact throughout the entire length of the vane rotor in the axial direction (thickness direction), resulting in significantly increased sliding resistance and frictional wear. It is hard to avoid the increase.
[0012]
Even if the valve timing changer can be combined so that the axial alignment accuracy between the vane rotor and the housing is sufficiently high, even if the minute gap between the vane rotor and the housing can be made constant all around the vane rotor, the pressure It is difficult to reduce the minute gap so that the oil tightness of the chamber can always be sufficiently maintained. The reason is as follows.
[0013]
The expected temperature range of hydraulic oil in an internal combustion engine is 100 degrees or more. The vane rotor and the housing are made of an aluminum alloy, and the driven gear is made of an iron-based sintered alloy. One end of the housing in the axial direction is fastened to the driven gear with a bolt. Therefore, the driven gear side (base end side) of the housing expands with the linear expansion coefficient of the driven gear, and the side far from the driven gear (front end side) expands with the linear expansion coefficient of the housing material itself to expand the housing in the radial direction. The rate is not uniform. Therefore, the minute gap between the vane rotor and the housing is designed to have a margin so that the vane rotor and the housing do not come into contact with each other even if the temperature of the hydraulic oil changes within a predetermined range, and therefore the oil tightness is low. I have to.
[0014]
SUMMARY OF THE INVENTION An object of the present invention is to provide a valve timing changing device that can ensure oil tightness of a required pressure chamber without using a seal member such as a seal plate and can be configured with a small number of parts. Another object of the present invention is to provide a valve timing changing device that can easily align the housing and the vane rotor without using a seal member. Furthermore, another object of the present invention is to provide a valve timing changing device that can ensure the required oil tightness of the pressure chamber with a smaller number of seal members than the conventional device.
[0015]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides the following means.
(1) A valve timing changing device that can change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and receives rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear. A driven rotating body that rotates coaxially with the camshaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft.
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor,
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
The inner periphery of the housing is provided with at least one protrusion extending inwardly,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
The side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, the side that is away from the driven rotator is referred to as a distal end side, and the gap between the inner periphery of the housing and the outer periphery of the vane rotor is defined as the front end side. g, when the gap g at the distal end is a and the gap g at the proximal end is b, at room temperature, a is almost 0 or a slight value, and b> a is there
A valve timing changing device characterized by that.
(2) The valve timing change as described in (1) above, wherein the a is so small that the outer periphery of the vane rotor and the inner periphery of the housing slide along the entire circumference at the tip end. apparatus.
(3) The gap (g) between the end on the distal end side and the end on the proximal end side is linearly increased from a to b. Valve timing changing device.
(4) The diameter of the vane rotor at the base end side is r, the difference between the linear expansion coefficient of the driven rotor and the linear expansion coefficient of the vane rotor is δc, and the predetermined maximum temperature Th of the fluid and the valve timing are fixed. The valve timing change as set forth in any one of (1) to (3), wherein b−a is approximately r * δc * δt, where δt is a difference from the temperature Tu of the fluid when releasing apparatus.
(5) When the thickness of the vane rotor in the axial direction from the end on the distal end side to the end on the proximal end side is w, a position P1 having an axial distance of about w / 10 or less from the end on the distal end side A step is provided on the outer periphery of the vane rotor or the inner periphery of the housing, and g = a between the end on the distal end side and the position P1, and between the position P1 and the end on the proximal end side. g = b
The valve timing changing device according to the item (1) or (2), wherein
(6) The valve according to any one of (1) to (5) above, wherein one of the bus forming the outer periphery of the vane rotor and the bus forming the inner periphery of the housing is parallel to the axis of the vane rotor Timing change device.
(7) A valve timing changing device that can change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and receives rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear. A driven rotating body that rotates coaxially with the camshaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft.
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor;
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
The inner periphery of the housing is provided with at least one protrusion extending inwardly,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
A side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, and a side away from the driven rotator is referred to as a distal end side, and an inner periphery of the space and an outer periphery of the vane in the housing. When the gap is g1, the gap g1 at the distal end is a1, and the gap g1 at the proximal end is b1, a1 is substantially 0 or a slight value at room temperature, b1 > A1,
A gap g2 between a trough that is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor and an inner periphery of the protrusion is constant,
The gap g2 is so small that oil tightness can be maintained, or is sealed with the seal member provided on the inner periphery of the protrusion.
A valve timing changing device characterized by that.
(8) A valve timing changing device that can change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and receives rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear. A driven rotating body that rotates coaxially with the camshaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft.
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor,
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
The inner periphery of the housing is provided with at least one protrusion extending inwardly,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
The gap g1 between the inner periphery of the space and the outer periphery of the vane in the housing is constant,
The gap g1 is small enough to maintain oil tightness or is sealed with a seal member provided on the outer periphery of the vane,
A side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, a side that is away from the driven rotator is referred to as a distal end side, and a plurality of vanes between the vanes in the circumferential direction of the vane rotor. When the gap between the valley that is the outer peripheral region and the inner periphery of the protrusion is g2, the gap g2 at the tip end is a2, and the gap g2 at the base end is b2, at room temperature, a2 is almost 0 or a slight value, and b2> a2
A valve timing changing device characterized by that.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments of the present invention.
[0017]
First, a first embodiment of the present invention will be described. 1A, 1B, 2A, 2B, 3, 4, and 5 show a first embodiment of the present invention. 1A is a front view of the vane rotor according to the first embodiment of the present invention as viewed from the front end side, FIG. 1B is a longitudinal sectional view taken along arrow WW in FIG. 1A, and FIG. ) Is a front view of the housing according to the first embodiment of the present invention as viewed from the base end side, and FIG. 2B is a longitudinal sectional view taken along the line XX in FIG. However, the configuration in which c1 = c2 = 0 in FIG. 2B is the first embodiment, and when c1, c2 ≠ 0, FIG. 2B shows the configuration of the first embodiment of the present invention. This is a modified example (detailed later). FIG. 3 is a cross-sectional view of an example that further embodies the first embodiment of the present invention (a view taken along the ZZ plane of FIG. 4 and viewed in the direction of the arrow. ~ 74, the structure excluding the washer 8 and the camshaft 4 is shown.). 4 is a vertical cross-sectional view taken along the line YY in FIG. FIG. 5 is an enlarged cross-sectional view showing a region G in FIG. 4 in order to explain the gap between the outer periphery of the vane rotor 1 and the inner periphery of the housing 2 in the embodiment of FIGS.
[0018]
The valve timing changing device according to the first embodiment includes a vane rotor 1, a housing 2, a sprocket 3 (corresponding to the driven rotor described above), a hexagon bolt 6 with flange, hexagon bolts 71, 72, 73, 74 with flange, and a washer. 8, positioning pins 9 (for positioning the housing 2 and sprocket 3, 2 in total) and non-rotating pins (for locking between the vane rotor 1 and the camshaft 4, 1 in total). The vane rotor 1 and the housing 2 are made of an aluminum alloy, and the sprocket 3 is made of an iron-based sintered alloy.
[0019]
The vane rotor 1 is fastened to the end surface of the camshaft 4 (left end surface in FIG. 4) with a hexagon bolt 6 with a flange. The entire valve timing changing device of this embodiment is attached to one end of the camshaft 4 and attached to one side of the engine block. Therefore, in the valve timing changing device of the present invention, the side closer to the camshaft 4 is referred to as the base end side, and the side far from the camshaft 4 is referred to as the front end side.
[0020]
1A, 1B, 3 and 4, the vane rotor 1 includes a through hole 12, a washer contact surface 14, a camshaft contact surface 13, oil grooves 15, 16, Oil holes 1e8, 1f8, 1g8, and 1h8 are provided in the boss portion, and vanes 1a, 1b, 1c, and 1d extending in the radial direction from the boss portion are provided. In FIG. 1, the oil grooves 15, 16 and the oil holes 1e8, 1f8, 1g8, 1h8 are omitted. Between the vanes 1a, 1b, 1c and 1d in the vane rotor 1, valleys 1e, 1f, 1g and 1h are formed, respectively. The tip surfaces of the vanes 1a, 1b, 1c and 1d form the outer peripheral surfaces 1a1, 1b1, 1c1 and 1d1 of the vanes, respectively. As shown in FIG. 1B, the feature of the present embodiment is that the diameter from the shaft oo to the outer periphery of the vane rotor 1 is large on the distal end side and small on the proximal end side, and the vane rotor 1 has a so-called tapered shape. This feature will be described in detail later.
[0021]
As often shown in FIGS. 2A, 2B, 3 and 4, the housing 2 has ridges 2e, 2f, 2g and 2h. Recesses 2a, 2b, 2c and 2d are formed between the protrusions 2e, 2f, 2g and 2h, respectively. The bottoms of the recesses 2a, 2b, 2c and 2d, and the surfaces equidistant from the axis of the housing 2 form the inner peripheral surfaces 2a1, 2b1, 2c1 and 2d1 of the housing 2 in the recesses 2a, 2b, 2c and 2d. Yes. Through-holes 21, 22, 23 and 24 are opened in the ridges 2e, 2f, 2g and 2h, respectively. The tip surfaces of the protrusions 2e, 2f, 2g, and 2h form inner peripheral surfaces 2e1, 2f1, 2g1, and 2h1, respectively. The housing 2 is provided with a hole into which a positioning pin 9 for aligning the axis with the sprocket 3 is fitted. The axis of the housing 2 passes through the center of the opening 25. Since two positioning pins 9 are provided at positions symmetrical with respect to the axis of the housing 2, two holes for positioning pins are also provided in the housing 2.
[0022]
The sprocket 3 appearing in FIG. 4 is a member corresponding to the driven gear in the apparatus disclosed in Japanese Patent Laid-Open No. 10-89020 mentioned above as an example of the prior art, and is supported on the camshaft 4 by a journal bearing. Rotational power is transmitted to the sprocket 3 from the crankshaft of the internal combustion engine via a chain. The sprocket 3 has teeth 30 fitted on the chain at the right end of FIG. 4 on the entire circumference, and as shown in FIG. 3, the oil grooves 3a, 3b, 3c, 3d and female threads 31, 32, 33, 34.
[0023]
The left end surface of the camshaft 4 in FIG. 4 is pressed against the camshaft contact surface 13 of the vane rotor 1. The outer periphery of the camshaft 4 has the same diameter as the outer edge 13a of the camshaft contact surface 13, and is in close contact with the outer edge 13a. In FIG. 4, a hole for a rotation-preventing pin is provided on the left end surface of the camshaft 4, and a similar hole for a rotation-preventing pin is provided at a position corresponding to the hole on the camshaft contact surface 13. The holes for the anti-rotation pins are aligned with the anti-rotation pins, and the rotation angle between the camshaft 4 and the vane rotor 1 is fixed. A female screw is provided at the left end of the camshaft 4 in FIG. 4 concentrically with the camshaft 4, and a hexagon bolt 6 with a flange is screwed to the female screw. The camshaft 4 is provided with oil passages 4a, 4b, 4c, 4d, an oil passage 4a1, and an oil groove 4e. As described above, FIG. 3 is drawn without the camshaft 4, but in FIG. 3, the oil passages 4a, 4b, 4c, 4d are represented by broken lines. The oil passages 4a, 4b, 4c, and 4d shown in FIG. 3 virtually represent the oil passages 4a, 4b, 4c, and 4d that appear when the camshaft 4 comes into contact with the proximal end surface of the vane rotor 1 in FIG. It is shown.
[0024]
The flanged hexagon bolt 6 is a fixing means for fastening the vane rotor 1 to the camshaft 4, passes through the through hole 12 of the vane rotor 1, and is screwed to the female screw of the camshaft 4. The hexagon head of the flanged hexagon bolt 6 is placed in the opening 25 of the housing 2. The flanged hexagon bolt 71 is a fixing means for fastening the housing 2 to the sprocket 3, passes through the through hole 21 of the housing 2, and is screwed into the female screw 31 of the sprocket 3. Similarly to the flanged hexagonal bolt 71, flanged hexagonal bolts 72, 73, and 74 that pass through the through holes 22, 23, and 24 and screw into the female screws 32, 33, and 34, respectively, are also provided. However, the flanged hexagon bolts 72, 73, 74 are not shown in the figure.
[0025]
The positioning pins 9 are pins embedded in holes formed in the end surface of the sprocket 3 (left side end surface in FIG. 4), and are provided at two symmetrical positions with respect to the axis of the sprocket 3 (however, , Only one positioning pin 9 appears). Thus, the end face of the sprocket 3 is provided with two protrusions made up of positioning pins 9. On the base end side end surface (the right end surface in FIG. 4) of the housing 2, positioning holes are formed at positions corresponding to the positioning pins 9 in the sprocket 3. The positioning hole of the housing 2 is fitted to the positioning pin 9 on the end face of the sprocket 3 and the hexagon bolts 71, 72, 73, 74 with flanges are screwed into the female threads 31, 32, 33, 34, and the housing 2 and the sprocket 3 Tighten. Since the positioning pins 9 are provided at two locations, the shaft centers of the housing 2 and the sprocket 3 coincide with each other with considerable accuracy, and the relative rotation angle between the housing 2 and the sprocket 3 is also set to a predetermined value.
[0026]
In the following description, it is assumed that the rotation direction of the housing 2 is the clockwise direction in FIG. At this time, the rotation direction of the sprocket 3 fixed to the housing 2 is naturally also the clockwise direction. The vane rotor 1 included in the housing 2 rotates at the same rotational speed as the housing 2 with a phase advanced or delayed with respect to the rotation of the housing 2. The phase depends on where the vanes 1a, 1b, 1c, 1d of the vane rotor 1 are located in the recesses 2a, 2b, 2c, 2d of the housing 2.
[0027]
As often shown in FIG. 3, in the rotational direction of the vane rotor 1, the recesses 2a, 2b, 2c and 2d of the housing 2 are partitioned by vanes 1a, 1b, 1c and 1d, respectively. The recesses 2a, 2b, 2c and 2d are partitioned by the vanes 1a, 1b, 1c and 1d, respectively, so that the advance pressure chambers 100a, 100a, are disposed on one side of the vanes 1a, 1b, 1c and 1d as viewed from the axial direction of the vane rotor 1. 101a, 102a and 103a are formed, respectively, and retard pressure chambers 100b, 101b, 102b and 103b are formed on the other side of the vanes 1a, 1b, 1c and 1d, respectively.
[0028]
In FIG. 3, since the rotation direction of the housing 2 is clockwise, when the vane 1a is in contact with the protrusion 2h, the rotation phase of the vane rotor 1 is most delayed with respect to the housing 2, and the vane 1a protrudes. The rotational phase of the vane rotor 1 is most advanced with respect to the housing 2 when in contact with the strip 2e. The advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b are respectively supplied with oil pressure from an oil control valve via an oil passage which will be described later.
[0029]
The hydraulic pressures of the advance pressure chambers 100a, 101a, 102a and 103a are common values. Let the hydraulic pressure of the advance pressure chamber be Pa. The hydraulic pressures of the retard pressure chambers 100b, 101b, 102b, and 103b are also common values. Let the hydraulic pressure in the retard pressure chamber be Pd. When Pa = Pd, the vane rotor 1 is stationary with respect to the housing 2, and the phase of the vane rotor 1 with respect to the housing 2 does not change. When Pa> Pd, in FIG. 3, the vane rotor 1 rotates clockwise relative to the housing 2, and the phase of the vane rotor 1 relative to the housing 2 advances from the current phase. When Pa <Pd, in FIG. 3, the vane rotor 1 rotates counterclockwise with respect to the housing 2, and the phase of the vane rotor 1 with respect to the housing 2 is delayed from the current phase.
[0030]
The limit of the rotational phase difference between the vane rotor 1 and the housing 2 is the range of the rotation angle in which the vanes 1a, 1b, 1c and 1d of the vane rotor 1 and the protrusions 2e, 2f, 2g and 2h of the housing 2 are not in contact with each other. It is. FIG. 3 shows a state in which the vane 1 a is in contact with the protrusion 2 h and the vane rotor 1 is in the phase most delayed with respect to the housing 2. When the vane 1a comes into contact with the protrusion 2e, the vane rotor 1 reaches the most advanced phase with respect to the housing 2.
[0031]
Next, oil passages for supplying hydraulic pressure to the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b will be described. On the outer periphery of the camshaft 4, annular oil grooves for advance and retard are formed. The advance and retard oil passages extending from the oil control valve communicate with the advance and retard oil grooves provided on the outer periphery of the camshaft 4, respectively. The camshaft 4 is provided with oil passages 4b and 4d leading to the annular oil groove for advancement provided on the outer periphery thereof, and oil passages 4a and 4c communicating with the annular oil groove for retarding angle. is there.
[0032]
Oil grooves 15 and 16 are formed in the camshaft contact surface 13 of the vane rotor 1. The advance oil passages 4b and 4d open to the oil grooves 15 and 16 on the end face of the camshaft 4, respectively. The diameter of the through hole 12 of the vane rotor 1 is larger than the diameter of the hexagon bolt 6 with a flange. Therefore, an annular space is formed between the inner periphery of the through hole 12 of the vane rotor 1 and the outer periphery of the flanged hexagon bolt 6. Oil grooves 15 and 16 communicate with the annular space. Oil holes 1e8, 1f8, 1g8 and 1h8 extend radially from the annular space in the vane rotor 1. The oil holes 1e8, 1f8, 1g8 and 1h8 open to the advance pressure chambers 100a, 101a, 102a and 103a, and communicate the annular space with the advance pressure chambers 100a, 101a, 102a and 103a.
[0033]
The oil passages 4a and 4c communicating with the retarded annular oil groove in the camshaft 4 are closed by the camshaft contact surface 13 of the vane rotor 1 at the end surface of the camshaft 4. The oil passage 4a communicates with the oil hole 4a1 at a position close to the end face. The oil passage 4c communicates with the oil hole 4c1 at a position close to the end face. However, the oil hole 4c1 does not appear in the figure. The oil holes 4a1 and 4c1 communicate with the annular oil groove 4e. The sprocket 3 is formed with oil grooves 3a, 3b, 3c and 3d which are close to the vane rotor 1 and extend from the end surface (left end surface in FIG. 4) contacting the housing 2 to the annular oil groove 4e. These oil grooves 3a, 3b, 3c and 3d open to the retard pressure chambers 100b, 101b, 102b and 103b, respectively.
[0034]
The advance hydraulic pressure Pa and the retard hydraulic pressure Pd are respectively supplied to the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b through the oil passages as described above. Thus, by controlling the hydraulic pressure of the advance pressure chambers 100a, 101a, 102a and 103a and the retard pressure chambers 100b, 101b, 102b and 103b by the oil control valve, the phase of the vane rotor 1 relative to the housing 2, and the crank The phase of the camshaft 4 with respect to the shaft can be arbitrarily controlled.
[0035]
As described above, the configuration and operation of the valve timing changing device according to the first embodiment of the present invention have been extended. As described above, the first embodiment is characterized in that the vane rotor 1 has a tapered shape. Next, operations and effects brought about by tapering the shape of the vane rotor 1 will be described.
[0036]
As described above, the vane rotor 1 and the housing 2 are made of an aluminum alloy, and the sprocket 3 is made of an iron-based sintered alloy. The vane rotor 1 and the housing 2 are made of an aluminum alloy in order to reduce the weight. Since the sprocket 3 is supported on the camshaft 4 by a bearing, it requires high strength. Therefore, iron-based sintered alloys showing high strength are widely used as the material for the sprocket 3.
[0037]
The temperature of the valve timing changing device almost depends on the temperature of the hydraulic oil supplied from the oil control valve. Shortly after the internal combustion engine is started or when the outside air temperature is low, the temperature of the hydraulic oil is low. When time has elapsed since the start of the internal combustion engine, and when the outside air temperature is high, the temperature of the hydraulic oil is high. When the hydraulic oil temperature is lower than the specified value, the lock pin is operated to fix the sprocket 3 and the camshaft 4 (or to fix the vane rotor 1 and the housing 2) and to change the valve timing to fix the valve timing. There are many devices, but even in such a valve timing changing device with a valve timing fixing function, the expected maximum temperature Th and valve during the period when the variable valve timing function is active (the period when the valve timing fixing function is released) The difference Δt from the temperature Tu when releasing the timing fixing function often exceeds 100 degrees Celsius.
[0038]
The linear expansion coefficient Cf of iron-based sintered alloy is 11 * 10^-6The linear expansion coefficient Ca of aluminum alloy is 21 * 10^-6It is about / ° C. When the aluminum alloy housing 2 is fastened to the iron-based sintered alloy sprocket 3 with bolts 71, 72, 73, 74, the rigidity of the iron-based sintered alloy is much greater than that of the aluminum alloy. Therefore, the vicinity of the sprocket 3 in the housing 2 (the end on the base end side of the housing 2) expands and contracts with the linear expansion coefficient Cf of the sprocket 3. On the other hand, the end portion on the front end side of the housing 2 expands and contracts with the linear expansion coefficient Ca of the aluminum alloy.
[0039]
As described above, in the conventional valve timing changing device, if no seal plate is used, the inner periphery of the housing 2 and the outer periphery of the vane rotor 1 are separated by a minute gap. In the conventional valve timing changing device having such a structure, the outer diameter of the vane rotor 1 and the inner diameter of the housing 2 are constant at room temperature regardless of the distance from the sprocket 3 in the axial direction. At this time, when the gap between the inner circumference of the housing 2 and the outer circumference of the vane rotor 1 is g, the gap g at the end on the distal end side is a, and the gap g at the end on the proximal end side is b (see FIG. 5) Is b = a.
[0040]
In this conventional valve timing changer structure, when operating at a temperature higher than 100 degrees above normal temperature, the gap g differs significantly depending on the distance from the sprocket 3 in the axial direction, and when the gap g at normal temperature is narrow, the housing 2 and the outer periphery of the vane rotor 1 are in contact with each other at the base end side, and whenever the valve timing is changed, a large friction is generated between the housing 2 and the vane rotor 1 to reduce the operation response. Unstable operation at low engine speed and wears the contact surface.
[0041]
In the structure of the conventional valve timing changing device, in order to avoid the contact between the inner periphery of the housing 2 and the outer periphery of the vane rotor 1 at the proximal end in high temperature operation, the linear expansion coefficient between the sprocket 3 and the vane rotor 1 The gap g at room temperature is uniform regardless of the distance from the sprocket 3 in the axial direction to the extent that the inner periphery of the housing 2 and the outer periphery of the vane rotor 1 do not contact each other even at the proximal end. The design must be large. However, when the gap g is increased as described above, the oil tightness between the advance pressure chamber and the retard pressure chamber is lowered, and the operation responsiveness is lowered.
[0042]
The above-mentioned two conflicting requirements in the conventional structure, namely the first requirement of maintaining oil tightness between the advance pressure chamber and the retard pressure chamber, and the contact between the vane rotor 1 and the housing 2 at a high temperature. In the present embodiment, the second requirement of avoidance is solved by providing the vane rotor 1 with a taper. In FIG. 1 (B), if the distance between the axis oo and the leading edge 1a2 of the outer peripheral surface 1a1 of the vane 1a is ra2, and the distance between the axis oo and the proximal end edge 1a3 of the outer peripheral surface 1a1 of the vane 1a is ra3, c1 = ra2-ra3.
[0043]
In this embodiment, the diameter of the vane rotor 1 at the base end side is r, the difference between the linear expansion coefficient Ca of the vane rotor and the linear expansion coefficient Cf of the sprocket 3 is δc, and the expected maximum hydraulic oil temperature Th and the valve timing are fixed. When the difference from the hydraulic oil temperature Tu when releasing the state is δt, and the difference c between the distal end side diameter r2 and the proximal end side diameter r3,
c ＝ r * δc * δt
It is.
[0044]
Here, an example is given about the vane 1a. Vane 1a diameter r = ra3 = 40mm on the base end side, linear expansion coefficient Cf = 11 * 10 of sprocket 3 (iron-based sintered alloy)^-6/ ℃, Vane Rotor 1 (aluminum alloy) linear expansion coefficient Ca = 21 * 10^-6/ ° C, δc = Ca-Cf = 10 * 10^-6/ ° C, maximum temperature Th = 130 ° C, hydraulic oil temperature Tu = 30 ° C when releasing the valve timing fixed state, δt = Th-Tu = 100 ° C,
c1 = 40mm * 10 * 10^-6/ ℃ * 100 ℃ ＝ 40 * 10^{− Three}mm = 40μm
It becomes.
[0045]
The outer peripheral surface 1a1 of the vane 1a is a tapered surface that gradually decreases in diameter linearly as it approaches the proximal side edge 1a3 from the distal side edge 1a2. The surfaces of the valleys 1e, 1f, 1g, and 1h in the vane rotor 1 are similarly tapered surfaces. However, since the diameter rf3 (the distance between the axis oo and the base end side edge 1f3) of the base end side of the valley is smaller than the diameter ra3 of the base end side end face of the vane 1a, c = r * δc * as described above. When the formula of δt is applied, c2 is smaller than c1 by the amount of small r. In the vane rotor 1 of FIG. 3, rf3 = 22.4 mm = 0.56ra3 and c2 = 0.56c1 = 22.4 μm.
[0046]
Now, referring to FIG. 5, in this embodiment, the diameter of the inner periphery of the housing 2 is constant in the axial direction (c1 = c2 = 0 in FIG. 2B). In the vane rotor 1, the difference c2 between the diameter re2 on the distal end side and the diameter re3 on the proximal end side of the valley 1e is the difference between a and b, and a−b = c2. Here, the diameter re3 (= rf3) of the valley portion 1e on the base end side is 22.4 mm, and a−b = c2 = 22.4 μm.
[0047]
In the first embodiment of the present invention, the vane rotor 1 is tapered as described above at normal temperature (temperature of the hydraulic oil when releasing the fixed timing of the valve Tu = temperature near 30 ° C.). . Therefore, for example, when the temperature of the hydraulic oil rises to 130 ° C., the vane rotor 1 and the housing 2 both expand at the same rate on the tip side of the valley portion 1e, so the gap g = a remains. On the other hand, on the base end side, the vane rotor 1 extends more in accordance with the equation of r * δc * δt than the housing 2, and r = re3 (= rf3) = 22.4 mm, δc = 10 * 10^-6/ ° C, δt = 100 ° C, so the elongation is 22.4μm, the outer circumference of the valley 1e of the vane rotor 1 approaches the protrusion 2e of the housing 2 by the amount that the diameter is made small at room temperature, b = a, and the gap g has a constant value a in the axial direction.
[0048]
As described above, the housing 2 is positioned on the sprocket 3 by the positioning pin 9, and the axis of the housing 2 coincides with the axis of the sprocket 3, that is, the axis of the camshaft 4 with considerable accuracy. However, it is not possible to make the housing 2 axis almost completely coincide with the camshaft 4 axis so that the vibrations caused by the eccentricity of the housing 2 axis from the camshaft 4 axis and the uneven wear are negligible. It was practically difficult due to production cost limitations. However, in the first embodiment of the present invention, if the gap a on the tip side is manufactured to a value close to zero so that the vane rotor 1 and the housing 2 slide in a room temperature environment, the housing 2 The rotation axis automatically matches the rotation axis of the camshaft 4.
[0049]
As described in detail above, in the valve timing changing device according to the first embodiment of the present invention, the vane rotor 1 is formed in a tapered shape, the gap between the inner periphery of the housing 2 and the outer periphery of the vane rotor 1 is g, and the tip When the gap g at the end on the side is a and the gap g at the end on the base end side is b (see FIG. 5), at room temperature, a is set to approximately 0 or a minute value, and b> a. With this configuration, a valve timing changing device that secures the required oil tightness of the pressure chamber without using a seal member such as a seal plate and requires only a small number of parts is realized. Furthermore, according to the first embodiment, a valve timing changing device that can easily align the housing and the vane rotor without using a seal member is realized.
[0050]
Next, a modification of the first embodiment will be described. In this modification, c1 = c2 = 0 in the vane rotor 1 of FIG. 1B, and the configuration of FIG. Other configurations are the same as those in the first embodiment. As means for realizing b> a in FIG. 5, in the first embodiment, the outer diameter of the vane rotor 1 is reduced from the distal end side to the proximal end side in the axial direction. The axial direction is increased from the distal end side toward the proximal end side. The operation and effect of this modification are the same as those of the first embodiment.
[0051]
Next, a second embodiment of the present invention will be described. FIGS. 1A, 1C, 2A, 2C, 3, 4, and 5 show a second embodiment of the present invention. However, the configuration in which c1 = c2 = 0 in FIG. 2 (C) is the second embodiment, and when c1, c2 ≠ 0, FIG. 2 (C) shows the configuration of the second embodiment of the present invention. This is a modified example (described later). The difference between the second embodiment and the first embodiment described above is that the vane rotor 1A has a step on the outer periphery as shown in FIG. In other configurations, the second embodiment is the same as the first embodiment. In the following description, it is assumed that the housing according to the second embodiment is denoted by reference numeral 2A in FIG. 2 (C) and c1 = c2 = 0 in FIG. 2 (C). C1 and c2 in FIG. 1C are designed by the same formula as c1 and c2 in FIG. 1B showing the first embodiment. In this stepped vane rotor 1A, the distance between the leading edge 1a2 on the outer peripheral surface 1a1 of the vane 1a and the proximal edge 1a3 on the outer peripheral surface 1a1 is H1, and the step on the leading edge 1a2 and the outer peripheral surface 1a1 When the distance from the surface 1a4 is H2, H2 / H1 = 1/10.
[0052]
In the second embodiment, since the inner diameter of the housing 2A is constant in the axial direction, the gap g between the vane rotor 1A and the housing 2A is a constant value a between the end surface on the tip side and the step surface 1a4. The constant value b is between the step surface 1a4 and the base end side end surface. In the second embodiment, as a means for realizing b> a in FIG. 5, a step is provided on the outer periphery of the vane in the vane rotor 1A. The step is formed at a distance of H2 from the front end surface, away from the front end side end surface by about 1/10 of the overall axial length H1 of the vane rotor 1A.
[0053]
In this second embodiment, the axial length of the remaining H1 / 10 slides with the inner peripheral surface of the housing 2 only by a length H2 that is about 1/10 of the overall axial length H1 of the vane rotor 1A. In this area, the outer periphery of the vane rotor 1A is spaced from the inner periphery of the housing 2. As described above, the axial center of the housing 2A becomes the axial center of the vane rotor 1A by sliding with the inner peripheral surface of the housing 2A only by a length H2 of about 1/10 of the overall axial length H1 of the vane rotor 1A. Can be matched with high accuracy. The accuracy with which the axis of the housing 2A matches the axis of the vane rotor 1A is superior to the accuracy in the first embodiment described above. Therefore, the shaft of the housing 2A can be almost perfectly aligned with the shaft of the camshaft 4 to such an extent that vibration due to the shaft of the housing 2A being eccentric from the shaft of the camshaft 4 and uneven wear can be ignored. It can be realized by its structural features. Since the axis of the housing 2A can be aligned with the axis of the vane rotor 1A with high accuracy, the gap b can be made sufficiently small, and therefore the oil between the advance pressure chamber and the retard pressure chamber can be provided without a seal member. The density can be increased sufficiently.
[0054]
Next, a modification of the second embodiment will be described. In this modification, c1 = c2 = 0 in the vane rotor 1A of FIG. 1 (C), and the configuration of FIG. 2 (C) is adopted as the housing 2A. Other configurations are the same as those of the second embodiment. As means for realizing b> a in FIG. 5, a step is provided on the outer periphery of the vane rotor 1A in the second embodiment, but in this modification, a step is provided on the inner periphery of the housing 2A. The operations and effects of this modification are the same as those of the second embodiment.
[0055]
Although the present invention has been specifically described with reference to the embodiments, it is needless to say that the present invention is not limited to these embodiments. For example, the driven rotator is the sprocket 3 in the above embodiment, but is not limited to the sprocket 3 and may be a belt or a gear. Further, the materials of the vane rotor 1, the housing 2, and the sprocket 3 are exemplified, but the material of the vane rotor 1 and the housing 2 is required to be lightweight, and the material of the sprocket 3 is required to be high strength. You can select from various materials in a range.
[0056]
The first embodiment of the present invention shown in FIG. 1 (B) and the modification of the first embodiment of the present invention shown in FIG. 1 (C) are combined, and both the vane rotor 1 and the housing 2 are pivoted. The diameter may be changed with respect to the direction, and the gap g between the vane rotor 1 and the housing 2 may be larger on the base end side than on the front end side. Similarly, the outer periphery of the vane rotor 1 and the housing are combined by combining the second embodiment of the present invention shown in FIG. 2B and the modification of the second embodiment of the present invention shown in FIG. Steps are provided on both inner peripheries of FIG. 2, and the gap g between the vane rotor 1 and the housing 2 is set to a within a slight axial length range from the tip side, and set to b over the remaining axial length range, a < It may be b.
[0057]
In the first embodiment described above, the outer peripheral surfaces 1a1, 1b1, 1c1, 1d1 of the vanes and the valley portions 1e, 1f, 1g, 1h of the vane rotor 1 are all tapered to provide the first embodiment. In the modification of the embodiment, both the inner peripheral surfaces 2a1, 2b1, 2c1, 2d1 of the recesses in the housing 2 and the inner peripheral surfaces 2e1, 2f1, 2g1, 2h1 of the protrusions in the housing 2 are both tapered or first In the second embodiment, both the outer peripheral surface of the vane and the valley portion of the vane rotor 1A are stepped. In the modification of the second embodiment, the inner peripheral surface of the recess in the housing 2A and the protrusion in the housing 2A are provided. Both of the inner peripheral surfaces of the strip were stepped.
[0058]
However, in the present invention, both the outer peripheral surface of the vane and the valley portion of the vane rotor 1 are both tapered (first embodiment), or the inner peripheral surface of the recess in the housing 2 and the protrusions in the housing 2 Either both inner peripheral surfaces are tapered (variation of the first embodiment), or both the outer peripheral surface of the vane and the valley of the vane rotor 1A are both stepped (second embodiment). ), Or both of the inner peripheral surface of the recess in the housing 2A and the inner peripheral surface of the protruding portion in the housing 2A need to be limited to any one (variation of the second embodiment). Absent.
[0059]
For example, the outer peripheral surface of the vane is tapered, the inner peripheral surface of the concave portion of the housing 2 is parallel to the axis, and the surface of the valley portion of the vane rotor 1 and the inner peripheral surface of the protruding portion of the housing 2 are the conventional ones described above. As in the example, the generatrix is parallel to the axis, so that the gap g2 between the surface of the valley of the vane rotor 1 and the inner peripheral surface of the protrusion of the housing 2 is constant, and the surface of the valley of the vane rotor 1 and the protrusion of the housing 2 are constant. Even in the configuration where the gap g2 is set to a value that is small enough to maintain the oil tightness between the inner peripheral surface of the strip, the oil tightness of the pressure chamber can be secured, the number of parts can be reduced compared to the conventional example, and the outer periphery of the vane The sliding resistance between the surface and the inner peripheral surface of the concave portion of the housing 2 can be reduced as compared with the conventional example for the same reason as the configuration of FIG. 1B, and the axis alignment between the vane rotor 1 and the housing 2 can be facilitated.
[0060]
As a similar configuration, for example, the outer peripheral surface of the vane is tapered, the inner peripheral surface of the concave portion of the housing 2 is parallel to the axis, and the surface of the valley portion of the vane rotor 1 and the protruding portion of the housing 2 are formed. The inner peripheral surface is parallel to the axis as in the above-described conventional example, and therefore the gap g2 between the surface of the valley portion of the vane rotor 1 and the inner peripheral surface of the protrusion portion of the housing 2 is constant, and the protrusion of the housing 2 is constant. Even if the sealing member is provided on the inner peripheral surface of the portion, and the oil tightness of the gap g2 between the surface of the valley portion of the vane rotor 1 and the inner peripheral surface of the protruding portion of the housing 2 is maintained by the sealing member, Oil-tightness can be secured, the number of parts can be reduced compared to the conventional example, and the sliding resistance between the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 is reduced from the conventional example for the same reason as the configuration of FIG. The vane rotor 1 and the housing 2 can be made by a smaller number of seal members. The sliding resistance of the can be reduced compared with the prior art, can also be easily axial alignment between the vane rotor 1 and the housing 2.
[0061]
In addition, the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2 have the bus line parallel to the axis as in the above-described conventional example, so the gap g1 between the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2 is constant. The gap g1 is set to a minute value so that the oil tightness between the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2 can be maintained, and the valley surface of the vane rotor 1 is tapered so that the housing 2 Even if the inner peripheral surface of the ridge part is configured so that the bus bar is parallel to the axis, the oil pressure in the pressure chamber can be secured, the number of parts can be reduced as compared with the conventional example, the surface of the valley part of the vane rotor 1 and the ridge of the housing 2 The sliding resistance with the inner peripheral surface of the portion can be reduced as compared with the conventional example for the same reason as in the configuration of FIG. 1B, and the axis alignment of the vane rotor 1 and the housing 2 can be facilitated.
[0062]
As a similar configuration, for example, the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2 have the bus line parallel to the axis as in the above-described conventional example, and therefore the outer peripheral surface of the vane and the inner peripheral surface of the concave portion of the housing 2. The gap g1 is constant with the outer surface of the vane, and a seal member is provided on the outer peripheral surface of the vane. The seal member keeps the oil tightness of the gap g1 between the inner peripheral surface of the recess of the housing 2 and the outer peripheral surface of the vane, Even if the inner surface of the ridge of the housing 2 is tapered in parallel to the axis, the oil pressure in the pressure chamber can be secured and the number of parts can be reduced compared to the conventional example. The sliding resistance between the surface of the valley and the inner peripheral surface of the ridge of the housing 2 can be reduced from the conventional example for the same reason as the configuration of FIG. The sliding resistance with the housing 2 can be reduced compared to the conventional example. In addition, the axis alignment of the vane rotor 1 and the housing 2 can be easily performed.
[0063]
In the preceding four paragraphs, the gap between the outer peripheral surface of the vane and the inner peripheral surface of the recess of the housing 2 is g1, and the gap between the valley surface of the vane rotor 1 and the inner peripheral surface of the protrusion of the housing 2 is g2. Of the gap g1 and the gap g2, only one of the gaps is made smaller on the distal end side and larger on the proximal end side, and the other gap is made constant. Even if the structure is made small enough to maintain the seal or sealed with a sealing member, the sliding resistance between the vane rotor 1 and the housing 2 is reduced, the number of parts is reduced, and the axis alignment between the vane rotor 1 and the housing 2 is performed. It is said that there is an effect in facilitating. In the preceding four paragraphs, only the modified example of the configuration of FIG. 1 (B) was given, but the same configuration can be obtained by similarly modifying the configuration of FIG. 2 (B) in which the inner periphery of the housing 2 is tapered. It is obvious that the effect can be obtained, and that the same effect can be obtained even if the configurations of FIGS. 1C and 2C are similarly modified.
[0064]
【The invention's effect】
According to the present invention, as described in detail above with reference to the embodiments, the valve timing can be configured with a small number of parts while ensuring the oil tightness of a required pressure chamber without using a seal member such as a seal plate. A change device can be provided. Furthermore, according to the present invention, it is possible to provide a valve timing changing device that can easily align the housing and the vane rotor without using a seal member. In addition, according to the present invention, there is provided a valve timing changing device that can secure the required oil tightness of the pressure chamber with a smaller number of seal members than the conventional device and that allows easy alignment of the housing and the vane rotor. Can be provided.
[Brief description of the drawings]
FIG. 1A is a front view of a vane rotor according to a first embodiment of the present invention as viewed from the front end side thereof, FIG. 1B is a longitudinal sectional view taken along arrow WW, and a vane rotor according to a second embodiment of the present invention; It is WW longitudinal cross-sectional view (C) which shows this.
2A is a front view of the housing according to the first embodiment of the present invention as viewed from the base end side, and FIG. 2B is a longitudinal sectional view taken along the line XX of the housing according to the modification of the first embodiment; In addition, it is a XX longitudinal sectional view (C) showing a housing in a modified example of the second embodiment of the present invention.
3 is a cross-sectional view (cut along the ZZ plane in FIG. 4 and viewed in the direction of the arrow in FIG. 4 except that the bolts 6 and 6 in FIG. 71 to 74, the structure excluding the camshaft 4 is shown.).
4 is a longitudinal sectional view taken along the line YY in FIG. 3;
5 is a cross-sectional view showing an enlarged region G in FIG. 4 in order to explain the gap between the outer periphery of the vane rotor 1 and the inner periphery of the housing 2 in the embodiment of FIGS. 3 and 4. FIG.
[Explanation of symbols]
1 ... Vane rotor (impeller)
1A ... Stepped vane rotor
1a, 1b, 1c, 1d ・ ・ ・ ・ ・ Vane
1a1,1b1,1c1,1d1 ・ ・ ・ ・ ・ Vane outer peripheral surface
1a2: Edge edge of outer peripheral surface 1a1
1a3: Base side edge of outer peripheral surface 1a1
1a4... Stepped surface formed on the outer peripheral surface of the vane 1a in the stepped vane rotor 1A
1a5 ・ ・ ・ ・ ・ Outer circumferential surface of vane 1a in stepped vane rotor 1A
1e, 1f, 1g, 1h ... Vane rotor valley
1e1 ... Outer peripheral surface of valley 1e
1e8,1f8,1g8,1h8 ... Oil holes extending radially from the through hole 12
1f1 ... Outer peripheral surface of valley 1f
1f2: Tip side edge on the outer peripheral surface 1f1 of the valley 1f
1f3: Base end side edge on the outer peripheral surface 1f1 of the valley 1f
1f4: Stepped surface formed on the outer peripheral surface of the valley 1f in the stepped vane rotor 1A
1f5: Outer peripheral surface of valley 1f in stepped vane rotor 1A
12... Through hole into which a bolt 6 for fixing the vane rotor 1 to the camshaft 4 is inserted
13 ... Camshaft contact surface in vane rotor
13a ・ ・ ・ ・ ・ Outer edge of camshaft contact surface
14 ...... Washer (washer) contact surface
14a ...... Outer edge of washer contact surface
15 ... Oil groove
16 ... Oil groove
100a, 101a, 102a, 103a ・ ・ ・ ・ ・ Advance pressure chamber
100b, 101b, 102b, 103b ・ ・ ・ ・ ・ retarding pressure chamber
2 ... Housing
2A ... Stepped housing
2a, 2b, 2c, 2d ... concave
2a1,2b1,2c1,2d1 ・ ・ ・ ・ ・ Inner peripheral surface of the housing in the recess
2a2... Edge side of inner peripheral surface 2a1 in recess 2a
2a3: Base end side edge of inner peripheral surface 2a1 in recess 2a
2a4... Stepped surface formed on the inner peripheral surface of the recess 2a in the stepped housing 2A
2e, 2f, 2g, 2h ... ridge
2e1,2f1,2g1,2h1 ・ ・ ・ ・ ・ Inner peripheral surface of ridge
2f2: Tip side edge on the inner peripheral surface 2f1 of the protrusion 2f
2f3: Base end side edge on the inner peripheral surface 2f1 of the protrusion 2f
2f4: Stepped surface formed on the inner peripheral surface of the protrusion 2f in the stepped housing 2A
2f5 ... Inner circumferential surface of the protrusion 2f in the stepped housing 2A
21,22,23,24 ...... Through holes into which bolts for fixing the housing 2 to the sprocket 3 are inserted
25... Open for receiving the hexagon head of the bolt 6 that secures the vane rotor 1 to the camshaft 4
26 ・ ・ ・ ・ ・ End face of the base end side of the housing 2
3 ... Sprocket
3a, 3b, 3c, 3d: Oil groove provided on the end face of the sprocket and communicating with the oil groove 4e
30 ... Teeth
31,32,33,34 ... Female thread provided on the tip side of the sprocket to which the bolt is screwed
35 ・ ・ ・ ・ ・ End face of sprocket
4 ... Camshaft
4a, 4b, 4c, 4d: Oil passages provided in the camshaft
4a1: Oil hole that connects oil passage 4a to oil groove 4e
4e: An annular oil groove formed on the outer periphery of the camshaft
6 ... Hexagon bolt with flange for fixing the vane rotor 1 to the camshaft 4
71 ...... Flanged hexagon bolt that passes through the through hole 21 and is screwed into the female screw 31 to fix the housing 2 to the sprocket 3
71a: Hex head of bolt 71
71b: Flange provided on hexagon head 71a
8 ...... Washer (washer)
9 ... Positioning pin
a: Clearance between the outer peripheral surface 1e1 of the valley 1e of the vane rotor 1 and the inner peripheral surface 2e1 of the protrusion 2e of the housing 2 on the tip end side of the vane rotor 1
b: Clearance between the outer peripheral surface 1e1 of the valley 1e of the vane rotor 1 and the inner peripheral surface 2e1 of the protrusion 2e of the housing 2 on the base end side of the vane rotor 1
c1... radial difference between the leading edge and the proximal edge on the outer peripheral surface of the vane of the vane rotor 1 (or the leading edge and the proximal end on the inner peripheral surface of the recess of the housing 2). The radial difference from the edge of the
c2: Radial difference between the leading edge and the proximal edge on the outer peripheral surface of the valley of the vane rotor 1 (or the leading edge on the inner peripheral surface of the protrusion of the housing 2) (Difference in the radial direction from the proximal edge)

Claims (8)

A valve timing changing device that makes it possible to change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and cams by receiving rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear A driven rotating body that rotates coaxially with the shaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft;
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor,
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
The inner periphery of the housing is provided with at least one protrusion extending inwardly,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
The side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, the side that is away from the driven rotator is referred to as a distal end side, and a gap between the inner periphery of the housing and the outer periphery of the vane rotor. g, where the gap g at the distal end is a and the gap g at the proximal end is b, at normal temperature, a is almost 0 or a slight value, and b> a There is a valve timing changing device. 2. The valve timing changing device according to claim 1, wherein the a is so small that the outer periphery of the vane rotor and the inner periphery of the housing slide along the entire periphery at the end on the front end side. 3. The valve timing changing device according to claim 1, wherein the gap g between the end on the distal end side and the end on the proximal end side increases linearly from a to b. 4. The diameter of the vane rotor on the base end side is r, the difference between the linear expansion coefficient of the driven rotor and the linear expansion coefficient of the vane rotor is δc, and the fixed state of the maximum temperature Th of the fluid and the valve timing is released. 4. The valve timing changing device according to claim 1, wherein b−a is approximately r * δc * δt, where δt is a difference from the temperature Tu of the fluid at the time. When the thickness of the vane rotor in the axial direction from the end on the distal end side to the end on the proximal end side is w, the vane rotor is at a position P1 having an axial distance of about w / 10 or less from the end on the distal end side. A step is provided on the outer periphery of the housing or the inner periphery of the housing, and g = a between the end on the front end side and the position P1, and g = b between the position P1 and the end on the base end side. The valve timing changing device according to claim 1, wherein the valve timing changing device is a valve timing changing device. 6. The valve timing changing device according to claim 1, wherein one of the bus forming the outer periphery of the vane rotor and the bus forming the inner periphery of the housing is parallel to the axis of the vane rotor. A valve timing changing device that makes it possible to change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and cams by receiving rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear A driven rotating body that rotates coaxially with the shaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft;
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor;
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
On the inner periphery of the housing, at least one ridge extending inward is provided,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
A side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, and a side away from the driven rotator is referred to as a distal end side, and an inner periphery of the space and an outer periphery of the vane in the housing When the gap g1 is a1, the gap g1 at the distal end is a1, and the gap g1 at the proximal end is b1, a1 is substantially 0 or a slight value at room temperature, b1 > A1,
A gap g2 between a trough that is an outer peripheral region between the plurality of vanes in the circumferential direction of the vane rotor and an inner periphery of the protrusion is constant,
The valve timing changing device according to claim 1, wherein the gap g2 is small enough to maintain oil tightness or is sealed with the seal member provided on the inner periphery of the protrusion. A valve timing changing device that makes it possible to change the valve timing of at least one of an intake valve and an exhaust valve of an internal combustion engine, and cams by receiving rotational power from a crankshaft through power transmission means such as a belt, a chain, and a gear A driven rotating body that rotates coaxially with the shaft, a housing fixed to the driven rotating body, and a vane rotor fixed to the camshaft;
The linear expansion coefficient of the driven rotor is smaller than the linear expansion coefficient of the housing and the vane rotor,
The driven rotating body is supported by the camshaft via a bearing so as to be relatively rotatable,
The housing has a space containing the vane rotor,
The inner circumference of the housing and the outer circumference of the vane rotor are separated from each other by a small gap or are in contact with each other in a selected region,
The inner periphery of the housing is provided with at least one protrusion extending inwardly,
The rotational angle range in which the vane of the vane rotor and the protrusion are in non-contact with each other defines the rotational phase difference limit between the vane rotor and the housing,
An advance pressure chamber and a retard pressure chamber are formed by dividing the space by the vane in the rotation direction of the vane rotor,
In the apparatus for rotating the vane rotor and the housing relatively by selectively supplying fluid pressure to the advance pressure chamber and the retard pressure chamber, and changing the valve timing,
The gap g1 between the inner periphery of the space and the outer periphery of the vane in the housing is constant,
The gap g1 is small enough to maintain oil tightness or is sealed with a seal member provided on the outer periphery of the vane,
A side of the housing and the vane rotor that is close to the driven rotator is referred to as a base end side, a side that is away from the driven rotator is referred to as a distal end side, and a plurality of vanes between the vanes in the circumferential direction of the vane rotor. When the gap between the valley that is the outer peripheral region and the inner periphery of the protrusion is g2, the gap g2 at the tip end is a2, and the gap g2 at the base end is b2, at room temperature, a2 is a valve timing changing device characterized in that a2 is almost 0 or a minute value, and b2> a2.

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